Catalytic technologies for the complete conversion of lignocellulosic biomass into fuels and chemicals

R. Le Van Mao
Le Van Mao Biochemicals Inc.,

Keywords: lignocellulosic biomass, catalytic conversion, levulinic acid and carboxylic acids, hydrocarbons, lignin catalytic depolymerization


Catalytic technologies for the complete conversion of lignocellulosic biomass into fuels and chemicals Raymond Le Van Mao (1,2) (1) Le Van Mao Biochemicals Inc., 1172 Alexis-Nihon, Saint-Laurent QC H4R 1S2 Canada (2) Industrial Catalysis Laboratory, Department of Chemistry and Biochemistry, Concordia University, Montreal QC H3B 1R6 Canada e-mail: Biomass is a renewable carbon source from which fuels and a variety of chemicals can be produced. In recent years, several processes of catalytic conversion of lignocellulosic biomass have been developed in our laboratories, essentially aiming at using forest residues and agricultural wastes as raw materials. Fenton’s chemistry is being used to convert cellulose and hemicellulose components of lignocellulosic biomass into carboxylic acids and their corresponding ethyl esters. Representative of such carboxylic acids is levulinic acid (our BTCA process: biomass-to-carboxylic acids [1]). In another process (our AC3B process: biomass-to-hydrocarbons [2-5]), these carboxylic acids are subsequently converted, over ZSM-5 zeolite catalysts, into gasoline-grade hydrocarbons (C5-C11), light olefins such as ethylene and propylene, and BTX aromatics. Conceptually, these conversion technologies are based primarily on a treatment for ‘’disruption-opening’’ of the protective layer of lignin of the biomass material (ex. wood). Then, through such partial structural aperture, catalytically active species present in the reaction medium (herein: acidic species), can have access to the cellulose and hemicellulose components. Such remarkable disruptive action is believed to result from the strong cracking effect of highly energetic free radicals generated by the Fenton’s reagent. The solid residue of BTCA or AC3B processes still has the structure of lignin. However, it is seriously degraded because of the cleavage of some ether bonds, mostly β-O-4 bonds, during such pre-treatment phase. Thus, such lignin char when treated again with the Fenton’s reagent, obviously under much higher severity condition, undergoes an advanced cracking to alkyl-aromatics and carboxylic acids. Therefore, by using Fenton’s reagent in both operations (biomass treatment/conversion of cellulose and hemicellulose, and catalytic depolymerization of the resulting lignin char), it is possible to completely convert lignocellulosic biomass materials into commercially valuable chemicals and fuels such as levulinic acid, other carboxylic acids, hydrocarbons and alkyl-aromatics. The latter compounds may be used for tailoring the renewable bio-jet fuels. References: [1] R. Le Van Mao, ‘’Catalytic conversion of lignocellulosic biomass into industrial biochemicals’’, PCT CA2017/050361 (March 24, 2017). [2] R. Le Van Mao, ‘’Catalytic conversion of lignocellulosic biomass into fuels and chemicals’’, WIPO/PCT WO 2013/127006 A1 (6 September 2013); EP 2819986 (May 31, 2017). [3] Innovation award (AC3B technology), TechConnect, Innovation Summit, Washington D.C., June 15-18, 2014. [4] R. Le Van Mao, A. Muntasar, D. Petraccone, H.T. Yan, ‘’AC3B technology for Direct liquefaction of Lignocellulosic Biomass. New concept of Coupling and Decoupling of Catalytic/Chemical Reactions for Obtaining a Very High Overall Performance’’, Catalysis Letters 142 (2012) 667-675. [5] R. Le Van Mao, Q. Zhao, G. Dima, D. Petraccone, ‘’New Process for the Acid-Catalyzed Conversion of Cellulosic Biomass (AC3B) into Alkyl-levulinates and other esters using a unique one-pot system of reaction and product extraction’’, Catalysis Letters, 141 (2011) 271-276.